This invention relates to a transmitter having an array antenna which is composed of a plurality of antenna elements.
A transmitter is known which has an array antenna composed of a plurality of antenna elements. Such a transmitter will be called an array antenna transmitter which may be used in a cellular mobile communication system. The array antenna transmitter forms a directional pattern by which a maximum transmission gain is obtained in concern to a direction of arrival of a desired or a reception signal, in order to prevent the array antenna transmitter from interference on transmission.
In a conventional array antenna transmitter, the antenna elements are arranged circularly to form the directional pattern of transmission gain that is almost uniform in every direction. As a result, it is difficult to obtain a high transmission gain proportional to the number of antenna elements, as will be described later.